DNS related changes

- Added hostname provisioning
- Added nsswitch.conf provisioning
- Added systemd-resolved provisioning

templates/nsswitch.j2

@@ -0,0 +1,20 @@
+# {{ ansible_managed }}
+#
+# If you have the `glibc-doc-reference' and `info' packages installed, try:
+# `info libc "Name Service Switch"' for information about this file.
+# See /usr/share/libc-bin/nsswitch.conf for an example of a configuration file.
+
+passwd:         files
+group:          files
+shadow:         files
+gshadow:        files
+
+hosts:          mymachines resolve [!UNAVAIL=return] files myhostname dns
+networks:       files
+
+protocols:      db files
+services:       db files
+ethers:         db files
+rpc:            db files
+
+netgroup:       nis